System and method for sequential driving of information handling system display backlight LED strings

Abstract

An information handling system display backlight illuminates an image with plural strings of LEDs driven by a backlight driver integrated circuit with pulse width modulation. A string detection module detects the number of active LED strings and divides the time period by number of active LED strings into an equal number of time delays or shifts so that the backlight driver sequentially turns on an LED string at a predetermined time period. The active number of LED strings is detected by reading a total number of LED strings from a management interface and subtracting from the total number any detected failed LED strings or any LED strings powered down to reduce power consumption.

What is claimed is: 
     
       1. An information handling system comprising:
 plural processing components operable to process information; 
 a display interfaced with the processing components and operable to present the information as visual images, the display having a backlight to illuminate the visual images, the backlight having plural sets of at least one LED; and 
 a backlight driver operable to drive the sets of LEDs according to a cycle, the backlight driver further operable to determine the number of sets of LEDs being driven, to apply the determined number to determine a sequencing time delay and to sequentially drive the sets of LEDs based on the sequencing time delay. 
 
     
     
       2. The information handling system of  claim 1  wherein the LEDs comprise RGB LEDs. 
     
     
       3. The information handling system of  claim 1  wherein the LEDs comprise WLEDs. 
     
     
       4. The information handling system of  claim 1  wherein the backlight driver determines the sequencing time delay by dividing the cycle by the number of sets of LEDs being driven. 
     
     
       5. The information handling system of  claim 4  wherein the backlight driver is further operable to detect failure of a set of LEDs and to adjust the sequencing time delay according to the number of LEDs being driven after detecting the failure. 
     
     
       6. The information handling system of  claim 1  wherein the backlight driver determines the number of sets of LEDs being driven by obtaining the number of sets of LEDs from a management interface. 
     
     
       7. The information handling system of  claim 6  wherein the backlight driver determines the number of sets of LEDs being driven by subtracting a number of failed sets of LEDs from the number obtained from the management interface. 
     
     
       8. The information handling system of  claim 6  wherein the backlight driver determines the number of sets of LEDs being driven by subtracting a number of sets of LEDs shut down to conserve power from the number obtained from the management interface. 
     
     
       9. The information handling system of  claim 1  wherein the backlight driver drives the sets of LEDs with pulse width modulation. 
     
     
       10. A method for sequential driving of plural LED sets, the method comprising:
 detecting an active number of the LED sets; 
 analyzing the active number of LED sets to determine a sequencing time delay for sequential driving of the LED sets; and 
 sequentially driving the LED sets with the sequencing time delay between the driving of each LED set. 
 
     
     
       11. The method of  claim 10  sequentially driving the LED sets comprises applying pulse width modulation to each LED set over a cycle. 
     
     
       12. The method of  claim 10  wherein analyzing the active number of LED sets further comprises retrieving the number of LED sets from a management interface. 
     
     
       13. The method of  claim 10  wherein analyzing the active number of LED sets further comprises detecting failed LED sets. 
     
     
       14. The method of  claim 10  wherein analyzing the active number of LED sets further comprises detecting that one or more LED sets are powered down to conserve power. 
     
     
       15. The method of  claim 10  wherein analyzing the active number of LED sets further comprises determining the sequencing time delay by dividing a cycle time period by the active number of LED sets. 
     
     
       16. The method of  claim 10  wherein the LED sets comprise WLEDs disposed as LED strings to backlight an information handling system display. 
     
     
       17. A system for driving LED strings of a display backlight, the system comprising:
 a string detection module operable to detect a number of active LED strings of the display backlight; and 
 a string sequence module operable to sequentially drive the LED strings over a time period, the time period broken into an evenly divided number of time delays equal to the detected number of active LED strings. 
 
     
     
       18. The system of  claim 17  wherein the string detection module detects the number of active LED strings by querying a management interface. 
     
     
       19. The system of  claim 17  wherein the string detection module detects the number of active LED strings by subtracting a number of detected failed LED strings from a total number of LED strings. 
     
     
       20. The system of  claim 17  wherein the string detection module detects the number of active LED strings by subtracting a number of powered down LED strings from a total number of LED strings.